During the operation of an aircraft, numerous on-board components and subsystems are continuously or periodically monitored. Various methods for monitoring these components and sub-systems of the aircraft have been used. For example, sensors and/or transducers can be mechanically affixed to an aircraft at specific locations so as to produce signals indicative of various physical phenomena experienced at those specific locations. In some embodiments, to interrogate structures of concern, one or more transducers can generate an acoustic signal and couple the generated acoustic signal to the aircraft at the specific location(s) at which the one or more transducers are affixed. Additionally, acoustic sensors can be affixed to locations of the aircraft and then can sense the acoustic condition at the affixed locations and generate signals indicative of the sensed acoustic condition. These signals can then be transmitted to an analyzer that interprets the signals received by the analyzer.
The analyzer can then compare the received signals indicative of the sensed acoustic condition with baseline and/or reference signals. If the sensed acoustic signals are sufficiently different from the baseline and/or reference signals, the analyzer can generate an alert signal and/or control the transducers so as to perform a more detailed probing of the acoustic condition of the aircraft to monitor the health of the aircraft. Such health monitoring scans can take a long time to perform if much detailed information is required. Such detailed health monitoring scans can require high power and/or energy to complete.
Optical sensors and/or transducers can produce optical signals indicative of various physical phenomena, and with low power requirements. For example, optical sensors and/or transducers can produce optical signals indicative of stress, strain, temperature, tilt, rotation, vibration, pressure, etc. Various sensors and/or transducers employ various types of technologies. For example, some sensors use Fabry-Pérot Interferometry (FPI). Some sensors use Fiber Bragg Grating (FBG) technologies. Some sensors use intensity modulation techniques. Some of these technologies and techniques produce optical signals having a spectrum that is indicative of the measured parameter. This disclosure is directed to the use of a distributed network of optical sensors for monitoring and/or sensing the acoustic condition of an aircraft structure, impacts to that structure, and for triggering a health monitor scan in response to the sensed acoustic condition.